Technology for analysing the biological rhythms of a user involves performing analysis according to image data obtained by imaging the user, concerning whether or not a user is likely to succumb to drowsiness. In the field of medical instruments, technologies have long been used for this purpose. However, in recent years, the field of application has suddenly expanded, leading to realisation of applications in the automotive industry and in the home appliance industry. One application of biological rhythms analysis technology is a wakefulness detection device that detects wakefulness. Wakefulness detection involves detecting an eye region in an image obtained by imaging a user, and then detecting eyelid droop and a blink count to determine whether the user is in a wakefulness state or a dozing state.